there's no built-in light-beam effect in anim8or; can't comment on terranim8or. the technique i used last time i wanted that type of effect involved creating an object with a single 4-sided poly, using an emissive material and textured with a specially-designed transparency map, stretched out long and thin - in my case 30 x 400. you can see the results (with several beams, in red) in my logo at the start of this video:

i've attached the texture file below; feel free to borrow it if you like